In terms of quality right out of the box the ETT modules are the best since the DRAM was tested and passed. Next would be the UTT modules that have a full data sheet, but have never been tested. Downgraded DRAM would be the least desired of the bunch as it is fallout memory that did not pass testing and does not have a full data sheet.
http://www.legitreviews.com/article.php?aid=218






